" 6.If "a=6,b=5,c=9" then "cos A=*

If a=6 , b=5 ,c=9 then angle A .

If tan ""A/2 =3/2, then (1+ cos A)/(1- cos A)= ................ A) -5 B) 5 C) 9/4 D) 4/9

In Delta ABC if a: b: c = 7 : 8: 9 , then cos A : cos B : cos C =

If in a /_\ ABC, a=6, b=3 and cos(A-B)= 4/5 then (A) C=pi/4 (B) A=sin^-1 2/sqrt(5) (C) ar(/_\ ABC)=9 (D) none of these

If A={5,6,7} and B={7,8,9} then A uu B is equal to a) {5,6,7,8,9} b) {5,6,7} c) {7,8,9} d) None of these

If 3 sin A+5 cos A =5, then the value of (3 cos A-5 sin A )^(2) is................. A) 4 B) 5 C) 2 D) 9

In DeltaABC, a = 3, b = 5, c = 6 , find the value of : cos (A/2)